Am in love with a girl who do not even care about me an d have caught her cheating on me.When I ask for a break up she refuse but yet she do not pay attention to me after all the pains she is putting me through. What should I do please help me

Leave her alone. You don't need permission to do that.

Break up with her and end it. Why are you asking for a break up? You need her to agree with you? Just tell her it's over and stop being with her.